The present invention relates to improvements to screening apparatus, particularly mobile screening apparatus which can be transported from site to site and can be used to screen material such as soil, sand, gravel, rubble and refuse. A particularly effective screening apparatus is the screening apparatus known as xe2x80x9cViper Sizer 122xe2x80x9d which is manufactured and sold by Viper International Limited. It has a vibrating screen box mounted on a frame located between a fifth wheel coupling and rear wheels and has a stock pile conveyor extending from the centre of the apparatus rearwardly over the wheels for use to form a stock pile of material which is being screened by the vibrating screen box.
This type of apparatus has proved so popular that a smaller version known as a xe2x80x9cMini-Sizerxe2x80x9d has been produced which has many of the advantages of the larger machine but which is still too expensive for many smaller operations such as small quarries, golf and sports clubs.
The main disadvantage of the prior art apparatus is that while the screening apparatus is effective, material has to be brought to the apparatus by an excavator, a loader with a shovel or the like. Therefore, as the regulatory authorities insist more and more upon compulsory screening of all rubble and refuse before it is accepted at disposal sites, it is necessary for any demolition job to have two pieces of apparatus on site at any one time, i.e. the screening apparatus and an excavator or loading shovel for bringing the material to be screened to the screening apparatus which although is located on site, cannot easily be moved during the actual screening operation.
The object of the invention is to alleviate the disadvantages associated with the prior art apparatus, particularly for small site work.
Accordingly, the present invention provides a screening apparatus which is removably connectable to a prime mover, having an excavating bucket or loading shovel which can be used to load unscreened material into the screening apparatus mounted on the prime mover.
Advantageously, material conveying means are removably attached to the prime mover whereby material may be loaded onto the conveyor by means of the loading or excavating bucket. The conveying means conveys the material to the screening apparatus mounted on the prime mover.
Conveniently, the screening apparatus may be one of a number of screening devices such as a vibrating screen or trommel screen.
Conveniently, the prime mover is a back-hoe loader of the type having an arm extending rearwardly with an excavating shovel and a pair of arms extending forwardly of the prime mover and for retaining a loading shovel.
Preferably, the front arms of the prime mover are used to support the screening apparatus which then can be elevated to the particular height required.
Additional jacking elements can be attached to the prime mover in order to stabilise the prime mover during any screening mode of the operation.
Alternatively, the present invention provides a screening apparatus in which the prime mover is a tracked excavating machine and the apparatus is mounted to one side of the tracked excavating machine.
Advantageously, the prime mover is a tracked excavating machine and the apparatus is centrally mounted on the tracked excavating machine, with the cab and engine of the excavating machine being mounted on a pedestal to allow a central conveyor of the apparatus to pass between the cab and engine and the tracks.
Conveniently, the screening apparatus is mounted on supporting framework extending to the rear of the excavating machine, with one or more further conveying means being provided to convey screened material from the apparatus.
Preferably, the further conveying means comprises a rear conveyor and one or more side conveyors.
Preferably, the hydraulically powered lifting means are provided for varying the height and angle of the conveying means and screening means.